I have the chance to purchase a Merc 165 boat engine which is built on the GM 230 CID engine. My question for this group is what differences are there internally between a 230 pick up truck engine and the 165 Merc.? I also have a "not so good" 250 CID and would like to put all the best pieces from both engines and end up with a decent driver 250. Those that may be able to help me with this subject, please do. Al
Mercruiser has a habit of putting some pretty radical grind cams in their marine engines, but without doing a check with a degree wheel and a dial indicator it would be hard to say what might be there. You might also find a set of forged pistons in the Mercruiser. The bore size on the engines will be the same- - - -the difference in displacement comes from a longer stroke crankshaft, and pistons with a different compression height in the 250. Check both engines for taper wear in the bore, and use whichever block has the best condition cylinders. If you really want a 250, the crank and pistons from the 230 won't work. The block, heads, and connecting rods should swap OK. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Yep- - - -it looks like Mercruiser didn't use any 230 engines, only 250's. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
hmmmm, I thought I scouted out the engine number which suggested a 230 CID, (information from an Internet chart). I certainly could be wrong in how I read the chart! I will get those numbers again and post them here so a confirmation of what the Merc 165 actually is, can be verified. Does the 165 refer to horse power or something else? I assume HP. Also, I am guessing that the Merc will have a hydraulic lifter cam? If the Merc is a 250, will I be able to bolt up a conventional flywheel and clutch to the crank? Al
Yes, 165 refers to HP. Some of the Mercruiser sixes had a Rochester 2-barrel carb on a special intake manifold, I believe. If that one's available, definitely use it. The crankshaft should accept a normal flywheel or flex plate, so bolting up a transmission won't be a problem. The exhaust for the Mercruiser is water-cooled so it will need to be swapped for a non-marine manifold. Using a block casting number to identify a 230/250 doesn't work, as the same block casting was used for both engines. Measuring the stroke is the only sure way to tell the difference. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Hey Hotrod, Do you have any thoughts or information on the type of lifters were used by Merc? Chev. did not send out any 250's that would have been rated at 165, did they? Al
The highest-rated 250 truck engine I've found specifications on is a 1980 with a 2 barrel carb, rated at130 HP at 4K RPM, and 210 ft/lbs. of torque at 2K. Earlier and later engines had less. The quickest way to beef up a 250 is to run 307 V8 flat top pistons, and a hotter cam. To get any real performance, a lot of cylinder head work needs to be done. "There's no substitute for cubic dollars" where head mods are concerned! Big valves, porting and a "lump port" setup can really turn a 250 on, but it's E$$$$$$PENSIVE!
I believe the 230/250/292 uses the same lifters as a small block V8 but I'm not sure of that. If so, the same "anti pump-up" lifters we used on the round track engines would probably work. Check with Comp cams to see what they offer in the way of performance type lifters for the 3rd-generation stovebolt engines.
OK- - - -just did a little research- - - - -the 194 through 292 stovebolt sixes do use the same lifters as a small block V8. The standard Comp Cams lifter is their part number 812. The anti pump up lifter that resists valve float and lifter top-out is their number 858. I've used the 858 lifters in 6K + RPM round track V8's. They really do work well with the right adjustment procedure. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Just like the old Sun test equipment slogan- - - - -"We test, not guess!"- - - -get out the degree wheel and dial indicator and give us some numbers. There are three stages of discussion about camshafts- - - -WAG, SWAG, And T-LAR. Here's how they translate:
Then there's the right way (and the only way with a used cam)- - - - -do a timing and lift check to see what you're actually dealing with. Anything else is a worthless waste of time. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I’ve been researching the 165 since I read this post. The general consensus seems to be the 165 has a cam similar to a “RV/Truck” cam. From the boats I’ve had in the past, I’m willing to bet that’s the case. They pulled hard in the 3800-4200 range, but started falling flat around 4500. One thing to remember is marine engines have a mechanical advance distributor, not vacuum. Also, they are void of emissions equipment, no egr, some don’t even have a pcv. Instead of an air cleaner they have a spark arrester. I believe this is why horsepower numbers are north of what automotive numbers are. On my boat with a Ford 302, it didn’t have a harmonic balancer. The rear engine coupling with it’s elastomer filling served as the balancer.
I also have done a bit of research on the OEM cam fitted to the 250 CID Mercruiser Marine 165 engine. Here is what the cam spec's. are if I were to purchase a new cam today. Duration .192/.192 Lift .403/.403 @ .050 Total Duration . 288/.288 @ .004 I have not evaluated any RV or otherwise performance cams to get a comparison. Al
Al it is reading wrong for clarification the duration of 192 degrees is at .050, seat duration is 288 degrees at .004 ramp Total gross lift is .403"
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
A 288 cam is pretty lumpy for a street machine, particularly if it's used with an automatic transmission. An automatic will need a higher stall speed torque converter, and a vacuum reservoir would come in handy if you plan to use power brakes. There will be a pretty good idle lope and erratic manifold vacuum. A fairly low geared rear end and/or a BUNCH of gears will be needed to keep it from bogging down leaving a stoplight. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I did a basic internet search looking for "RV Cams". The above listed cam specifications seem to be in close proximity to what is listed as an "RV" cam on the internet from several vendors. Of course, each cam MFG'er has their own flavor or variation of "RV" cam grinds and tout their offering as far superior to the competition offerings. I wish I would have more experience with Cam specifications and terminology, sadly all I can do is compare numbers and driving experiences with the different cams I have owned in the past. Potentially this engine, or the best parts in combination with another 250 pickup engine will be installed in a 1946 Chev. 1.5 ton truck. I will also be replacing the original crash box transmission with a slightly newer version with syncro rings and ease of shifting. The low gearing, in the stock rear end, will be an asset for the cam listed above. The truck is going to be stock excepting the engine and transmission. Al
Here is the next phase of the Merc 165 story. I will be bringing it home in the next week. I should take the head off quickly as it is very tight to roll over. I suspect that it has had water come through the carb. into the engine. I also will be missing the fuel pump and the distributor. If the bottom end is not scattered, I should have all the pieces I need to put together a 250 engine for the 1946 1.5 ton truck. The 165 does have a two barrel carb on it, but it appears to have an integral intake and exhaust manifold (water cooled marine unit) so I will be using the manifolds from my 250 truck engine and likely going back to a single barrel carb. Al
Hello Ed, I have got ideas on the radiator support modification to get enough elbow room for this longer engine and using the short water pump. What application should I look to for the short water pump. Has anyone come up with an adapter that will move the fan up a bit? Al
a HEI from a late model 250 (1980's) will be a drop-in fit. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Chevy "250 ci engine" in a 69 Chev NOVA === with a "short" (250) water pump. I have a 250 motor in my original 69 Nova with "Factory A/C" and 'Heavy Duty Cooling System' .... bought new in Phoenix, AZ. I'm the 2nd owner -- I know the "Grand-Pa's son & grandson". Here's some "250 motor water pumps form a regular 250 motor (standard water pump -- car motor) -- compared to a 292 ci ( from a 1-ton truck) == long style water pump. And, a 'core water pump' from my 250 (155hp - factory a/c installed) 69 NOVA (again, a car engine - if there's any difference).
Alan